Mt Fuji may erupt by 2015, says Ryukyu University professor

Since the Great Tohoku Earthquake of March 2011, scientists have been anxiously watching the massive volcano known as Mt Fuji for signs of activity. In September of last year, a report was released stating that Mt Fuji’s magma chamber pressure had risen to a worrisome 1.6 megapascals, which is estimated to be higher than when it last erupted.

According to retired professor Masaki Kimura of Ryukyu University, this and other recent phenomena indicate an eruption of Mt Fuji should have taken place in 2011 with a four-year margin of error ending in 2015.

First, a little background on Mt Fuji. Japan sits on the edge of a “subduction zone” which is where one layer of the Earth’s crust is pushed under another. This pushing is an ongoing process and results in part of the Earth’s crust being pushed down into the hot magma of the Earth’s mantle. However, because this crust is saturated with water, it mixes differently with the magma in the mantle causing a lighter material to rise back up through the top layer of crust.

This rising magma then becomes a magma chamber. Here, away from the mantle, various gases are released from the magma and accumulate. When pressure becomes stronger than the rock containing it, the rock pops open in a volcanic eruption.

Mt Fuji was formed in this manner, and the subduction which occurs during large-scale earthquakes is believed to cause an increase in the magma chamber. The previous 1707 eruption of Mt Fuji is said to have been triggered by a massive earthquake occurring near Osaka a month before.

Prof Kimura believes that aside from the Tohoku earthquake there has been an overall increase in more “normal” seismic activity around the mountain – particularly on its northeast side.

“Magma is rising from beneath Mt Fuji. Cracks in the crust have been growing. Some things hanging above have been falling. No one is pointing it out, but I think there is a possibility.”

By “things hanging”, Prof Kimura is possibly alluding to the partial collapse of the Sasago expressway tunnel in December last year, which killed nine. Authorities are still investigating the cause of the collapse and no earthquake was detected at the time, but deformation of the tunnel is speculated as being the cause.

Prof Kimura also mentions the rise of the water level at Lake Sai which is located to the northeast of Mt Fuji. At the time of the Tohoku earthquake, the lake’s water-level rose by one meter. Kimura believes that this was caused by the permafrost near Fuji’s summit melted by rising magma.

Prof Kimura also claims that there have been a large number of phreatic eruptions – explosions of steam caused by heating of ground water from rising magma – around the mountain. No lava is released during these explosions, only water and rock.

However, some say that phreatic eruptions are precursors to major volcanic eruptions. Prior to the 1980 eruption of Mt Saint Helens in the US, there were numerous reports of phreatic eruptions. This is a theory which Prof. Kimura seems to agree with.

“It looks like the danger of eruption is in the northeast corner of Mt Fuji, but there is also a possibility of an eruption from the summit crater at the same time. Volcanic earthquakes are increasing, and their epicenters are becoming increasingly shallow.”

It should be noted that Prof Kimura is co-author of “Fujisan No Funka Wa Hajimatteiru!” (The Eruption of Mt Fuji Has Begun!), a book released in June last year, as well as author of 2011’s “Fujisan Dai Funka! Bukimina Itsutsu No Choko” (Mt Fuji’s Big Eruption! Five Eerie Signs).

Also, despite the evidence at hand it is still difficult to predict disasters like earthquakes and volcanic eruptions with absolute accuracy.

However, in the event of a Mt Fuji eruption, many speculate the cost to human life would be low due to the slow moving lava that would likely occur. On the other hand, the cost of damage to public and private property would undoubtedly be immense.

So if you’re planning purchasing any property in the vicinity of Mt Fuji, you might want to sit on it for a while.

49 Comments

Guess it's time to visit Fuji-san soon before things take a turn for the worse. Any eruption from a volcano that massive is going to be significant. The concern about lava flows is misplaced though--As with St. Helens, the main worry should be the initial force of super-heated gases and ash from the area where pressure is building. Something to really monitor!

"claims," "seems to agree", "possibly alluding to", and at the end a guy selling two books written in 2 years about the same topic.

Not saying it is not possible, but for anyone who can't read Japanese, now you have an example of the kind of sensationalist "expose'" fright writing that sells the weeklies (Friday and FLASH etc), which constantly run these kinds of stories alonside celbrity marriage breakdowns and true crime.

It would be scary if it happened, but there's always "% chance of earthquakes and tidal waves etc" stories and sometimes they are right sometimes wrong. Can't worry too much about it until it happens.

One explanation for supervolcanoes is the water that is dragged down to mix with magma during suboceanic subduction. In such a high-pressure state, the water, though well above boiling point, remains liquid in a state called a "super-critical fluid." Maintenance of pressure is key, for if the pressure drops below the level required to maintain supercriticality, the water will immediately convert to steam - a state far less dense and thus requiring far more space. This is an explanation for why supervolcanoes explode so suddenly and dramatically - it is akin to shaking a bottle of soda and then slightly removing the cap.

Aso, close to where I live, was purportedly the same height as Fuji long ago; it retains a similar footprint, but the mountain itself is gone; all that remains is the caldera, where the ground collapsed into the emptied magma chamber, and small peaks formed by subsequent eruptions.

Small releases of pressure should be monitored closely, and ideally, mathematical models formed to warn when pressures drop to supervolcano levels.

Interesting that this article completely ignored the fact that the magma chamber pressure is currently more than 10 times higher than during the last 50 years, well inside the zone considered to be critical.

Mt Fuji’s magma chamber pressure had risen to a worrisome 1.6 megapascals, which is estimated to be higher than when it last erupted.

So, apparently, we also have to worry about a Fuji eruption in addition to another massive earthquake close to Tokyo.... Mother nature, please, spare us. I don't even want to imagine the possibility of any of these two catastrophes occurring. Following the 2011, we all reached a point when we thought "ok the worst is over". Unfortunately, we must always be prepared for the worse. I hope that the J-gov conducts a plan for an emergency like a Fuji eruption or a Kanto earthquake and let us hope that it won't have to use it.

Yes Fuji might not erupt by 2015, but if the pressure in the magma chamber is measurably increasing, that does not bode well. At some point the seal over the magma chamber is going to rupture due to the increasing pressure, and it will NOT be pretty. Mt. St. Helens had a measurable bulge grow prior to the fatal eruption which was triggered by an earthquake that only measured 5.1 on the Richter scale. How many earthquakes of THAT magnitude does Japan experience every year?

For those saying "big deal" about the phreatic eruptions and the fractures widening, check out this bit of info from Wiki on the Mt. St. Helens' eruption:

The eruption was preceded by a two-month series of earthquakes and steam-venting episodes, caused by an injection of magma at shallow depth below the volcano that created a huge bulge and a fracture system on Mount St. Helens' north slope.

Finally, here's a drawing of what Mt. St. Helens looked like before it erupted. Look familiar?

He's not predicting doomsday. He's predicting a volcanic eruption, which is easier to do than predict earthquakes because there are more precursors we can measure with current technology. The precursors now point to an eruption, so I wouldn't toss this prediction into the same pile with the Mayan doomsday or the return of Elvis (though Elvis didn't die. He just went home.)

I just wanted to point out that the guy didn't really predict Fujisan would erupt in 2015, he predicted it would erupt in 2011 with a margin of error of +4 years. So he's already 40% into his predicted window with no eruption yet. I'm not sure why this article is making news NOW if his prediction came two years ago.

I can't watch "Japan Sinks" after the 2011 disaster which includes the nightmare scenario of the volcano erupting (but it doesn't)... and now this warning that Fuji is waking up. About time my friends and loved ones started looking at airline tickets!

What's really interesting is if you read the other links. Fish and wildlife have always been good early warning indicators of some event about to occur. Having lived here over a decade I've also noticed about the number of tremors in the Tokyo area and the intensity level of them.

The only mentioned level of deflection was the rise in the water and increased span of cracks on the surface. I'm surprised they aren't setting up laser measurement to catch a calculable change.

Earthquake prediction is far from being accurate , animals and fish have deeper senses (primitive) that acts as a alarm for self preservation. Perhaps scientist should not focus as much on man made devices to warn them of impending danger and get back in touch with natures system.

Fadamor, thx for the link to Mt St Helens, you could be forgiven for thinking its Fuji san.
and Farmboy is right its not a doomsday he is predicting ( unless of course you happen to be climbing Fuji san on the day it erupts ) and Elvis didn't necessarily go home, he just left the building..

Also, despite the evidence at hand it is still difficult to predict disasters like earthquakes and volcanic eruptions with absolute accuracy.

^This is point number one. it is difficult to predict these things with any accuracy, and yet he is being pretty specific by saying "by 2015". If he had solid evidence that this is going to happen with any degree of certainty, rather than writhing a book, he should be rallying up the media and government officials to get more researchers and geologists on the job so that they can gather more data on this to make a more accurate prediction.

However, in the event of a Mt Fuji eruption, many speculate the cost to human life would be low due to the slow moving lava that would likely occur.

^This is point number two.

I am not saying that Fuji-san won't erupt; it could erupt tomorrow for all I know. He may be 100% right in his prediction. What I am saying is that he is implying that Fuji's eruption is imminent and is going to be a cataclysmic event, hence the book. No one would be interested in reading a book with the title, "Mt Fuji’s Big Eruption! Five Eerie Signs" unless there were some doomsday or mass catastrophe element behind it.

In reality, the eruption may just be a a trickle of magma like mentioned in the article, or it could be massive explosion like St. Helen, but he doesn't which does he?

I think the predictions of volcanic eruptions are becoming more and more accurate. It's not a perfect science yet, but it's fairly good at narrowing the time frame. In this case, he has narrowed it to three years. When things start to rumble a bit, the predictions can become much more accurate, and people can be evacuated from the immediate area. Whether that will be enough remains to be seen. The following suggests that the eruption will be fairly large:

Mt Fuji’s magma chamber pressure had risen to a worrisome 1.6 megapascals, which is estimated to be higher than when it last erupted.

The last time Fujisan erupted, it had a big impact. There are, in fact, a lot of researchers on the job, and the mountain is being monitored by people from many universities, not just one.

As to your second point, you mention the part of the article which says that there will be little loss of human life, but you've ignored the next sentence:

On the other hand, the cost of damage to public and private property would undoubtedly be immense.

Please keep in mind that an eruption of Fujisan will most likely cut all traffic on the southern route, the Tomei expressway, and volcanic gas will most likely be blown in the direction of Tokyo, as the wind generally goes from west to east. A LOT of people may have to be moved within a relatively short time frame. Where will we put them?

There is a tendency toward disbelief when it comes to big changes in the world, probably because there are so many people who happily exaggerate risk. Most of the time, disbelief is the correct choice. This time, though, there is solid evidence that big changes are occurring, and I would suggest that rejecting this evidence needs to also be based on fact. Big changes do occasionally occur, and some of them CAN be predicted.

With all do respect to a previous poster. I think your term of super-volcano is a bit misplaced. There are only 6 known locations around the globe which have that distinction. The most famous being Yellowstone National Park in Wyoming & Montana. The Yellowstone region is often referred to as a (super-volcano) because it has spewed more than 240 cubic miles (a thousand cubic kilometers) of ash and lava in a single event. The most recent of these massive blasts occurred some 640,000 years ago.. Yellowstone's next major eruption will probably be centered in one of three parallel fault zones running north-northwest across the park, a new study predicts. Two of these areas produced large lava flows the last time the super-volcano was active some 74,000 to 70,000 years ago. While the third has had the most frequent tremors in recent years.

Scientists aren't sure yet but there is a possibility these super volcano sites around the world are connected somehow. As smaller eruptions which occur have shown to have effects on other areas such as Mt. Fuji volcanic chain of islands among others. These occur more frequently but the chance of one happening in any given year is still less than one in ten thousand. In contrast flows have fed the slow-growing lava dome at Mount St. Helens in the years after that volcano's major eruption, but Yellowstone's lava flows occur on a much grander scale. A friend of mine studies Yellowstone and he has said.

We have never seen a rhyolite eruption of this magnitude in human history & I hope we never will?

Some of the largest volcanoes in the world are shield volcanoes. The Hawaiian Islands are composed of linear chains of these volcanoes including Kilauea and Mauna Loa on the island of Hawaii which are two of the world's most active volcanoes. The floor of the ocean is more than 15,000 feet deep at the bases of the islands. As Mauna Loa, the largest of the shield volcanoes (and also the world's largest active volcano), projects 13,677 feet above sea level, its top is over 28,000 feet above the deep ocean floor.

Mt. Fuji in contrast is what is know as a composite volcano, also known as strato-volcano. Unlike the shield volcanoes which are flat and broad, composite volcanoes are tall, symmetrically shaped, with steep sides, sometimes rising 10,000 feet high. They are built of alternating layers of lava flows, volcanic ash, cinders, blocks, and bombs. Mt Fugi is in the same class of Volcano as Mount Cotopaxi in Ecuador, Mount Shasta and Lassen in California, Mount Hood in Oregon, Mount St. Helens and Mount Rainier in Washington, Mt Pinatubo in the Philippines, and Mt. Etna in Italy. So if comparisons should be made as to what type of eruption is possible here. These are good examples to go by. I hope this never happens as Mt. Fugi is to Japan what Mt. Rainier is to US.

Awhile before the 11/3/11 big one, one of the TV networks showed this really scary documentary about what scientists say could actually happen if Fuji were to have a major eruption, complete with that really scary music and graphics before and after every commercial break that Japanese TV channels always love. It was really an eye-opener and the facts noted really rang true so they didn't need the scary music to freak me out! Basically, it's all about wind direction. In the event of a major eruption, if the wind was blowing the speed and direction that it usually does, -right towards Tokyo, then the most populated areas of the Kanto plain would have tons of ash, razor sharp microscopic glass-like particles, that shred the inside of your lungs, dumped on it, so that literally millions would die, since the same ash particles would also clog all machinery so all traffic (trains,planes and cars) attempting to flee the ensuing chaos would be stopped along with all electricity and communications. Pretty scary stuff for those of us who live in the Kanto area.

Guess we can say that Japan's run for the 2020 Olympics is heating up. Ironic how one of the proposed US 2020 Olympic cities is close to another super-volcano (Yellowstone) showing signs of getting closer to eruption.

Reminds me when people "predicted" that Mt. Rainier will erupt...we're still waiting...
Reminds me when people claimed that the end of the world will be at Dec 21 2012....we're still here...
Reminds me when we had that Y2k scare...planes didn't fall from the sky...

Japan itself is part of a chain dotted with volcanoes many of which which go off every so often. (Look up Kamchatka, the Kuriles, and Sakhalin. Some beautiful voacanoes on a par or surpassing Fuji.) We have had eruptions all over Japan very recently and throughout history, and volcanic eruptions, earthquakes and typhoons all come under 'Weather' in J Yahoo. For this reason, although dormant, an eruption of Mt Fuji has to be considered possible, even likely.

Just looking for an easy-to-understand example here. If a teenager gets a spot/zit/plook on his face and it grows red and hot, then going on past experience, there is a good chance it will erupt. It may not be mathematically 100% provable, but the strong likelihood is there. This build-up of pressure in the magma chamber of Mt Fuji must be something similar.

I just hope it erupts through the central crater, and not out it's side like Mount St Helens. Fujiyama is a beautiful looking mountain with its symmetrical cone. Just like St Helens was before she blew her side open.

@T-Marie, Amen to that!
Do not be so skeptical about his prediction. It will happen, and probably sooner than later.
I dreamed about the big earthquake back in 2006 and about Mt. Fuji's eruption. What I saw was not
nice. The explosion was so great that it shook Tokyo, triggering lots of fires. Now, if you do not like what I dreamed, then delete my post. I did not make it up.

I'm no Ishihara but if Mt Fuji really erupts at this timing after what happened in 2011 I will have to believe in the will of a greater presence. Would however much prefer a different kind of divine incident such as, say, miraculously striking huge amounts of oil in the Tohoku region.

retired professor Masaki Kimura of Ryukyu University
It should be noted that Prof Kimura is co-author of "Fujisan No Funka Wa Hajimatteiru!" (The Eruption of Mt Fuji Has Begun!), a book released in June last year, as well as author of 2011's "Fujisan Dai Funka! Bukimina Itsutsu No Choko" (Mt Fuji's Big Eruption! Five Eerie Signs).

in sicily we know that when a vulcano erupts, it is telling the locals that the centre of the earth is too hot and just is letting out some steam, correct.

i sugest that japan hires koreans to go to the bottom of the ocean far from civilization and explode a few big korean bombs to open up the floor to let the earth cool off a little once in a while.

Comic, but sadly many people actually believe crazy statements like those to be facts. And probably the only thing you'll get with major blasts in the Nankai fault zone is an earthquake (and maybe the volcano to go off), but even that isn't likely.

Mt Fuji was formed in this manner, and the subduction which occurs during large-scale earthquakes is believed to cause an increase in the magma chamber. The previous 1707 eruption of Mt Fuji is said to have been triggered by a massive earthquake occurring near Osaka a month before.

The quake was "near Osaka" like Tokyo is "near Mt Fuji" pretty far way. And it wasn't one quake, rather five faults triggered in quick succession and isn't as common as the 2+2 or 2+3. Generally the Nankaido zone triggers one set every 100 years or so, with the last set being 1944/46, and the quakes might be related since 800-1100 had both Nankaido quakes and eruptions within a few years of each other. But Nankaido isn't likely to have more quake movements for another 20-30 years, so doubtful that will cause Fuji to go off.

Interesting that this article completely ignored the fact that the magma chamber pressure is currently more than 10 times higher than during the last 50 years, well inside the zone considered to be critical.

This is point number one. it is difficult to predict these things with any accuracy, and yet he is being pretty specific by saying "by 2015".

It's called a statistical evaluation, which people seem to take as truth or lies because they are ignorant of the underlying meaning. "By 2015" doesn't mean 100% chance by that time, it means the probability of eruption is greater than significant. This guy probably doesn't want to state what he considers significant, but we can assume he means a 95% confidence in his assumption that it will go off somewhere between 2009 and 2015 if he really thinks so (but more than likely we're talking about 50% or so, which is not really all that great a prediction.

If he had solid evidence

What is solid evidence? A full and accurate simulation? A piece of the volcano brought back through time? I'm sure he claims his works have solid evidence, but they might not be something you could even consider evidence.

that this is going to happen with any degree of certainty, rather than writhing a book, he should be rallying up the media and government officials to get more researchers and geologists on the job so that they can gather more data on this to make a more accurate prediction.

The government has always known about the risks, and this guy isn't the first to say it. Fuji erupts every few hundred years (well, switches between activity and inactivity), and has had a few major eruptions in the last million (it's actually three geologically different volcanoes stacked on top of each other, one of them wasn't even called Fuji though). Geologists and researchers have studied Fuji for a long time, recording everything from pressure and water to the height of the mound. All of that data points to increased likelihood of activity in a relatively short time frame.

What I am saying is that he is implying that Fuji's eruption is imminent and is going to be a cataclysmic event, hence the book. No one would be interested in reading a book with the title, "Mt Fuji’s Big Eruption! Five Eerie Signs" unless there were some doomsday or mass catastrophe element behind it.

Disaster does sell, and he probably does exaggerate everything. Very true statement there.

In reality, the eruption may just be a a trickle of magma like mentioned in the article, or it could be massive explosion like St. Helen, but he doesn't which does he?

Even the trickle of magma will also bring massive amounts of ash, which can disrupt air travel, damage rivers and dams, and can cause respiratory issues. Any activity in Fuji would be economically significant, even if it's not the end of the world. If it does go off like St Helen, or worse, we have a third Fuji (see above), then it can cause thousands of deaths and trillions of yen worth of economic damage. Luckily the chances of that are low, considering the historical records, but it's doubtful anyone can say how it will become active before it does (and likely only have a few days or weeks of warning for evacuations of the areas affected)